2604. Contact With School-Aged Children is a Major Risk Factor for Pneumococcal Colonization in Older Adults

BACKGROUND: Important questions remain about the role of older adults in driving transmission of pneumococcus in the community. This is a critical question for understanding the potential indirect effects of using pneumococcal conjugate vaccines (PCVs) in older adults. For non-institutionalized individuals, the most likely source of adult-to-adult transmission is in the household. The goal of this study was to characterize the dynamics and risk factors for acquisition of pneumococcus in older adults. METHODS: We designed a longitudinal study to sample adults > 60 years of age living in the same household (New Haven, CT), and without younger contacts residing in the household. Saliva samples and questionnaires regarding social behaviors and health status were obtained every 2 weeks for a period of 10 weeks. DNA extracted from culture-enriched saliva was tested using qPCR for pneumococcus genes piaB and lytA. RESULTS: Across the two study seasons (November 2020-August 2021, November 2021-September 2022), 184 individuals from 93 households were sampled and completed all 6 visits. Overall, 31/184 (16.8%) individuals were colonized on at least one time point based on qPCR detection of piaB. Two individuals were colonized at 6/6 time points, and two others were colonized at 5/6 time points during the 10-week sampling period. In 7/93 (7.5%) households, both members were colonized, though not necessarily at the same time point. Pneumococcal colonization was substantially higher among individuals who had contact with children < 18 years as compared to those with no recent contact with children (9.4% vs 2.3%). Participants who reported recent contact with < 5 year olds and 5-9 year olds had particularly elevated prevalence (14.3%; 13.0%, respectively). CONCLUSION: Pneumococcal acquisition related to adult-to-adult transmission is low. Contact with pre-school and young school-aged children was the most important factor that influenced acquisition rates of pneumococcus among older adult households. DISCLOSURES: Anne L. Wyllie, PhD, Co-Diagnostics: Board Member|Merck: Grant/Research Support|Pfizer: Advisor/Consultant|Pfizer: Grant/Research Support Ronika Alexander-Parrish, RN, MAEd, Pfizer, Inc.: Employee|Pfizer, Inc.: Stocks/Bonds Adriano Arguedas, Medical director, Pfizer: Emplyee|Pfizer: Stocks/Bonds Bradford J. Gessner, M.D., M.P.H., Pfizer: I am an employee of Pfizer|Pfizer: Stocks/Bonds Daniel M. Weinberger, PhD, GSK: Advisor/Consultant|Merck: Advisor/Consultant|Merck: Grant/Research Support|Pfizer: Advisor/Consultant|Pfizer: Grant/Research Support